1. Field of the Invention
The present invention concerns methods of treating skin with compositions containing certain esters of salicylic acid.
2. The Related Art
Skin is subject to deterioration through dermatologic disorders or normal aging (chronoaging) as well as extrinsic factors (environmental). Dermatologic disorders include such conditions as acne, dry skin, dandruff, keratosis, pruritus, inflammatory dermatoses, eczema, psoriasis and tenia pedis (athlete's foot).
Chronoaging results in the thinning and general degradation of skin. As skin naturally ages, there is reduction in the cells and blood vessels that supply the skin. There is also a flattening of the dermal-epidermal junction which results in weaker mechanical resistance. Older individuals increasingly develop facial fine lines, wrinkles, leatheriness, yellowing, sagging, mottling (hyperpigmentation), age spots and the general signs of aging.
Extrinsic factors are primarily those caused by exposure to sun. Changes are most prominent in light skinned individuals who burn easily and tan poorly. The results of photodamage may be identical to those of aging except appearing at an accelerated rate. Wrinkling, yellowing, leatheriness, mottling and hyperpigmentation are all associated with sun damage. Most disturbing to many individuals is the wrinkling effect. It is a prime reminder of the disappearance of youth. As a result, there have been many reports of cosmetic treatments aimed at the elimination of wrinkles.
PCT applications WO 93/10755 and WO 93/10756 report salicylic acid as an effective anti-wrinkling agent. U.S. Pat. No. 5,262,407 reports use of ring acylated salicylic acid as a treatment against skin aging. Salicylic acid has also been described for the treatment of acne in U.S. Pat. No. 4,891,227 and U.S. Pat. No. 4,891,228. Moreover, salicylic acid has been used for the removal of warts, corns and calluses; for the treatment of psoriasis, seborrheic dermatitis and dandruff; and for the topical treatment of ringworm infection. A listing of commercially available products containing salicylic acid will be found in the Physician's Desk Reference, 45th Edition, 1991, page 323.
Ring alkylated salicylic acid has been reported in Japanese Patent 4036238 (Takasago Perfumery KK) for treatment of acne vulgaris.
Significant irritation is often associated with the use of salicylic acid. Another problem is that salicylic acid is not always readily formulatable into oily compositions. Derivatives of salicylic acid most often leave the acidic function free. Irritation caused by acidity is therefore not prevented by such derivatives.
Accordingly it is an object of the present invention to provide a treatment for a variety of dermatologic disorders such as acne, dry skin, dandruff, keratosis, pruritus, inflammatory dermatosis, eczema, psoriasis and tinea pedis.
Another object of the present invention is to provide a treatment for chronoaging conditions including wrinkling and fine lines, leatheriness, yellowing, sagging, mottling (hyperpigmentation), age spots and the general signs of aging.
Still a further object of the present invention is to provide a treatment for acne and pimples.
Still another object of the present invention is to provide a treatment against environmental abuse to skin including wrinkling and fine lines, yellowing, leatheriness, mottling and hyperpigmentation.
Yet another object of the present invention is to provide a treatment to improve the condition of skin with a composition and active that does not impart irritation.
These and other objects of the present invention will become more readily apparent from the following summary and detailed discussion.